BAGHDAD/DUBAI, Jan 15 (Reuters) - Nuri al-Maliki's political skills have kept him at the pinnacle of power in Iraq since 2006, but the Shi'ite Muslim leader has yet to heal the wounds of a country traumatised by tyranny, occupation and communal strife.

His critics say he has exacerbated that legacy by gaining undue control over the army, police and security services and using them freely against Sunni Muslim and other political foes, while allowing grave abuses in prisons and detention centres.

Yet in April voters may well hand a third term to Maliki - a hardbitten political operator who emerged from obscurity to become prime minister nearly eight years ago - or at least give him a headstart in post-election wrangling for the job.

He spent much of his life before the U.S.-led invasion in 2003 in exile in Syria and Iran, plotting revolt and fearing betrayal.

Maliki was born in 1950 in Janaja, a southern village among date groves on the Euphrates, into a politically engaged family - his grandfather wrote poetry inciting rebellion against Iraq's British occupiers and his father was a fervent Arab nationalist.

He secretly joined the Shi'ite Islamist Dawa party as a youth, attending Baghdad University's Islamic law college before becoming a low-level bureaucrat in Hilla, south of the capital.

In 1979 he was briefly arrested and then fled, narrowly escaping Saddam's police. His family's land was seized and dozens of his relatives were killed over the next decade. He did not see his home village again until after the 2003 invasion.

That troubled history may colour his outlook today.

"UTTERLY RUTHLESS"

"He has proved a fantastically able manipulator of the scene and utterly ruthless," said Crispin Hawes, managing director of Teneo Intelligence, who has followed Maliki's career closely for years.

"That ruthlessness is partially explained by his entirely pragmatic view of Iraqi politics. His goal is solely to further the interests of his (Shi'ite) constituency."

Short on charm, he has a steely determination to best his enemies, especially after the 2010 parliamentary poll which the Sunni-backed Iraqiya bloc led by Iyad Allawi narrowly won, only to be outmanoeuvred and shut out by Maliki in the aftermath.

He may have won out against Allawi, a secular Shi'ite, securing a new mandate with Iranian and U.S. support after eight months of political infighting, but the initial shock defeat appears to have narrowed his ruling style.

A former senior adviser to Maliki is cited by Iraq expert Toby Dodge of the London School of Economics as saying the prime minister began keeping decision-making far more to himself after the formation of his government in 2010.

"Maliki's paranoia went stratospheric and he wouldn't listen to any advice," Dodge quoted the adviser as saying.

The election also discouraged Sunnis who, after boycotting earlier U.S.-sponsored elections, had put their faith in the ballot box and supported Iraqiya - only to see it stymied after its success. "It's against that background that violence and alienation has flourished in Anbar," Dodge said.

Maliki now faces a huge challenge from al Qaeda-linked militants who have taken over Falluja, in the Sunni heartland province of Anbar next to Syria, where they are also fighting.

He has demanded that Falluja tribes and citizens expel the gunmen, but says the army will not assault the city.

The 63-year-old, who struggled for decades against Saddam's Sunni-dominated regime as a member of the underground Shi'ite Islamist Dawa party, denies his outlook is sectarian.

"PERVERTS AND DEVIANTS"

"I am not fighting in Anbar because they are Sunnis, as I have also fought Shi'ite militias. Al Qaeda and militias are one - they both kill people and blow them up. Both rely on perverts and deviants," Maliki told Reuters this week,.

In 2008, he sent troops to suppress militias of rival Shi'ite factions which were controlling the oil hub of Basra.

Christopher Hill, another former U.S. ambassador to Iraq who worked with Maliki, said the Iraqi leader had paid a "steep price" among Shi'ites for that Basra intervention.

"This did not earn him a lot of support in the Shi'ite sectarian community," Hill said. "But it didn't earn him any credit in the Sunni community either."

Maliki lists ending sectarianism and militias among his core principles, along with promoting a strong, stable, unified and sovereign Iraq that poses no threat to its neighbours.

He must also balance relations with the United States, whose invasion brought Shi'ites to power, against those with Iran, which wields more influence in Iraq than the distant superpower.

Maliki, a proud Iraqi nationalist, says he is beholden to neither, wants good ties with both, and puts Iraq's interests first. "All sides understand the situation," he declared.

Hawes said Maliki had gone out of his way to maintain his relationship with the United States "against squeals of protests from Iran".

Maliki was also very cooperative with Tehran when it suited him, he added: "But he's not the sort of Iranian stooge that he's described as or often seen as by his opponents."

The United States has sent limited military aid to help Baghdad combat the Islamic State of Iraq and the Levant, an al Qaeda affiliate which is also fighting in Syria's civil war.

But Washington has also urged Maliki to reach out to Sunnis feeling disenfranchised in the post-Saddam era.

Maliki told Reuters the government would pay and arm anyone combating al Qaeda as part of "Sahwa" (Awakening) Sunni tribal militias that helped U.S. forces drive back the militants in Anbar in 2006-07.

FEAR OF SUNNI RESURGENCE

However, his offer may not herald political concessions to the Sunnis or a move toward genuine reconciliation - policy steps which would be hard to sell to his Shi'ite supporters, who are among the prime targets of al Qaeda suicide bombers.

"Like all Shi'ites, he's very nervous - they have this tremendous fear of the Sunnis rising up and putting the Shi'ites and the Kurds back in their place," said James Jeffrey, a former U.S. ambassador to Iraq.

Noting Maliki's efforts to restrain hotheads in his own community, he said Shi'ite militias had not retaliated lately against Sunni civilians as they had when al Qaeda unleashed the sectarian bloodletting of 2006-07 in which tens of thousands of Iraqis died.

"Maybe Maliki to some degree deserves some credit for that if he deserves some blame for inflaming the situation with the Sunnis," Jeffrey said.

"He's happy with the consequences to solidify Shi'ite votes behind him," said the London-based Dodge.

U.S. President Barack Obama, hosting Maliki in November, urged him to promote sectarian reconciliation, but American influence has waned since U.S. troops left two years ago.

"We have the leaders we have here, and we have to work with them as best as we can," a senior U.S. official said when asked whether Washington regarded Maliki as a leader who was sincerely interested in forging a more inclusive government.

Jeffrey said Maliki was not an easy man to influence.

"From my experience, if you threaten him and say we will not give you assistance, that is not going to compel him to do things he doesn't want to do because frankly he can turn to the Iranians or the Russians," the former U.S. envoy said. "He must prefer to turn to us though, to keep a balance."

Maliki, who is married with four children, says his job leaves him no time for anything outside politics and a career he says has been guided by the same principles throughout.

"I was who I am and will stay who I am," he told Reuters. "I do not have another hidden character." (Additional reporting by Suadad al-Salhy in Baghdad and Matt Spetalnick in Washington; Editing by Alastair Macdonald)